1. Field of the Invention
The present invention relates to a jetting error detector, a droplet jetting applicator, and a display device manufacturing method. More specifically, the present invention relates to a jetting error detector configured to detect a jetting error of a droplet jetting head for jetting droplets, a droplet jetting applicator including the jetting error detector, and a display device manufacturing method using the droplet jetting applicator.
2. Description of the Related Art
A droplet jetting applicator is typically used for manufacturing various display devices such as a liquid crystal display device, an organic EL (electro-luminescence) display device, an electron emission display device, a plasma display device and an electrophoretic display device. This droplet jetting applicator includes a droplet jetting head for jetting droplets from its multiple nozzles toward an application target. The droplet jetting head makes multiple droplets land on the application target, thereby forming dot arrays in a predetermined pattern so that various coated bodies (such as a color filter) are manufactured.
In such a droplet jetting applicator, whether or not a jetting failure will occur is generally checked prior to an application operation. Factors of this jetting failure include bubbles, dusts and so forth. Concerning bubble detection, there have been disclosed a technique for determining and detecting the presence of a bubble and a technique for determining whether or not a bubble adheres to a piezoelectric element (see JP-A No. 4-29851 and JP-A No. 11-334102, for example). Even if it is confirmed, prior to an application operation, that no jetting failure will occur, a jetting error such as a jetting failure or a jetting amount shortage may occur depending on the degree of contamination with bubbles, dusts and the like in the course of an application operation to perform application based on application pattern data. In particular, a jetting error may be caused by disturbance vibration, bubble growth or the like during the application operation.
However, according to the related art, it is not possible to detect the above-mentioned jetting error in the course of the application operation. Therefore, if a jetting error occurs, application defective items are continuously manufactured until the occurrence of the jetting error is found by an inspection in a different process. This leads to a decrease of production yield in the application process using the droplet jetting head.